Ephesians 6:10
Finally, my brethren, be strong in the Lord, and in the power of his
           Verse 10. Finally]  Having laid before you your great
  and high calling, and all the doctrine and precepts of
  the Gospel, it is necessary that I should show you the
  enemies that will oppose you, and the strength which
  is requisite to enable you to repel them.
     Be strong in the Lord]  You must have strength, and
  strength of a
spiritual kind, and such strength through
indwelling God, the power of his might working in
  you. (Adam Clarke, Clarke’s Commentary, A Classic
  Help of Better Understanding of the Bible, Matthew -
  Revelations:  Volume VI, Romans to Revelation
  (Nashville: Abington /World Publishing, 1977, 467-468)

     Here is a general exhortation to constancy in our
  Christian course, and to courage in our Christian
  warfare. Is not our life a warfare? It is so; for we
  struggle with the opposition of the powers of
  darkness, and with enemies who would keep us from
  God and heaven. We have enemies to fight against, a
  captain to fight for, a banner to fight under, and
  certain rules of war by which we are to govern our-
  selves. "
Finally, my brethren (v. 10), it yet remains that
  you apply yourselves to your work and duty as Christ-
  ian soldiers." Now it is requisite that a soldier be both
  stout-hearted and well armed. If Christians be soldiers
  of Jesus Christ.
      I. They must see that they be stout-hearted. This is
  prescribed here:
Be strong in the Lord, &c. Those who
  have so many battles to fight, and who, in their way to
  heaven, must dispute every pass, with dint of sword,
  have need of a great deal of courage.
Be strong there-
strong for service, strong for suffering, strong
  for fighting. Let a soldier be ever so well armed without, if he
  have not within a good heart, his armour will stand him in
  little stead. Note, Spiritual strength and courage are very
  necessary for our spiritual warfare. Be strong in the Lord,
  either in his cause and for his sake or rather in his strength.
  We have no sufficient strength of our own. Our natural                       
  courage is as cowardice, and our natural strength as                  
  perfect weakness; but all our sufficiency is of God. In his
  strength we mus go forth and go on. By the actings of
  faith, we must fetch in grace and help from heaven to
  enable us to do that which of ourselves we cannot do, in
  our Christian work and welfare. We should stir up ourselves to
  resist in a reliance upon God's all-sufficiency and the omnipotence
  of his might. (Matthew Henry, Matthew Henry’s Commentary of the
  Whole Bible, Volume VI., Acts to Revelation, Old Tappan: Fleming
   H. Revell Company, n.d.), 718).

                 Ephesians 6:11a
  Put on the whole armor of God . . .


Verse 11.  The apostle considers every Christian to have a
   warfare to maintain against numerous, powerful, and subtle foes;
   and that therefore they would need much strength, much courage,
   complete armor, and skill to use it. The
panoply  which is mentioned
   here refers to the armor of
heavy troops among the Greeks; those
   who were to sustain the rudest attacks, who were to sap the founda-
   tions of walls, storm cities, &c. Their ordinary armour was the
helmet, the sword, and the greaves or brazen boots. To all these
   the apostlerefers below. See on ver. 13.
 Ephesians 6:11b
    . . . that we may stand against the wiles of the devil.
   The wiles of the devil.] . . . The methods of the devil; the different
    means, plans, schemes, and mechanations, which he uses to deceive,
   entrap, enslave, and ruin the souls of men. A man's method of sinning
   is Satan's method of ruining his soul. See on chap. iv. 14. (Adam Clarke,
   Clarke's Commentary, A Classic Help of Better Understanding of the
   Bible, Matthew - Revelations:  Volume VI, Romans to Revelation (Nashville:
   Abington /World Publishing, 1977, 468)
   II. They must be well armed: "Put on the whole armour of God (v. 11),
   make use of all the prayer defensitives and weapons for repelling the
   temptations and stratagems of Satan-get and exercise all the Christian
   graces, the whole armour, that no part be naked and exposed to the
   enemy." Observe, Those who would approve themselves to have true
   grace must aim at all grace, the whole armour. It is called the armour of    
   God, because he both prepares and bestows it. We have no armour of
   our own that will be armour of proof in a tyring time. Nothing will stand
   us in stead but the armour of God. This armour is prepared for us, but
   we must put it on; that is we must pray for grace, we must use the grace
   given us, and draw it out in act and exercise as there is occasion. The
   reason assigned that the Christian should be completely armed is
   he may be able to against the wiles of the devil
-that he may be able to
   hold out,and to overcome, notwithstanding, all the devil's assaults,
   both of force and fraud, all the deceits he puts upon us, all the snares
   he lays for us. . . . (Matthew Henry, Matthew Henry’s Commentary of the
   Whole Bible, Volume VI., Acts to Revelation, Old Tappan: Fleming
   H. Revell Company, n.d.), 718
                   Ephesians 6:12

we wrestle not against flesh and blood, . . ."
             Verse 12. For we wrestle not against flesh and blood] Our wrestling
   or contention is not with men like ourselves: flesh and blood
is a
   Hebraism for
men, or human beings. . . .
 Here it signifies warfare in general.
       Against principalities] . . . beings of the first rank and order of their
       Powers] . . . derived from, and constituted from the above.
The rulers of darkness of this world] . . . The rulers of the world; the
emperors of the darkness of this state of things.
Spiritual wickedness] . . . The spiritual things of wickedness; or, the
   spiritualities of wickedness;
highly refined and sublimed evil; disguised
in the garb of truth; Antimonianism in the guise of religion.
In high places] . . . In the most sublime stations. But whom are these
   of whom the apostle speaks? . . . But commentators . . . think that by
   principalities, &c., we are under different orders of evil spirits, who are
   employed under the devil, their great head, to prevent the spread of the
   Gospel in the world, to destroy the souls of mankind.
spiritual wickedness are supposed to be the angels which kept
   not their first estate, who fell from the
heavenly places but are ever
   longing after striving to regain them; and which have their stations in
regions of the air. "Perhaps," . . . "the principalities and powers
remain mostly in the citadels of their kingdom of darkness; but there